1. Field of the Invention
This invention relates generally to photographic apparatus and particularly to a manually operated processing mechanism for use with an automatic camera adapted to sequentially expose and process a cassette of self-processable film units.
2. Description of the Prior Art
In the photographic industry the appearance of new film forms often plays the role of harbinger to invention. The present invention follows this pattern since it is a response to the need for a simplified manually operable processing system for use with film cassettes containing self-processable film units.
The type of cassette referred to basically comprises a box-like plastic housing containing a stack of self-processable film units as, for example, described in U.S. Pat. No. 3,415,644 issued to Edwin H. Land on Dec. 10, 1968, and entitled PHOTOGRAPHIC PRODUCTS AND PROCESSES. In these type of cassettes, each film unit is adapted to be consecutively exposed and subsequently withdrawn through an exit slot in the cassette and, afterwards, processed by being transported between a pressure generating nip defined by a pair of juxtaposed rollers located exterior to the cassette in close proximity to the exit slot.
The functions that a processing system must perform in order to satisfy the requirements imposed by such a film cassette are to: ( 1) selectively engage an individual exposed film unit within the cassette; (2) advance the engaged film unit from the cassette through its exit slot and into contact with the rollers; (3) rotate the rollers so that they further advance the film unit and process it as it is being moved through them; and (4) reinitiate the cycle to repeat the process in subsequent film units. Additionally, an energy source must be provided to supply the power required to drive the system.
In known manually driven processing systems for use with cassettes such as that described in U.S. patent application Ser. No. 485,795 entitled PHOTOGRAPHIC FILM CASSETTE filed on July 5, 1974, by Nicholas Gold, the mode of operation may be described as follows: (1) the rollers are caused to rotate by some suitable manual power input such as a crank or lanyard; (2) a film advance which is initially coupled to the rollers and driven in response to their rotation moves a film unit out of the cassette and into engagement with the rotating rollers; (3) a clutch or cam mechanicm interrupts the driving relationship between the film advance and the rollers after the film unit is operatively associated with the rollers; (4) the power input continues to rotate the rollers and completes the processing of the film unit; and (5) a hold-release mechanism temporarily keeps the film advance out of contact with a subsequent film unit until a prior exposed film unit has been processed and the release feature actuated. Systems in the prior art exhibiting these characteristics are, for example, U.S. Pat. No. 3,757,657 entitled MANUALLY OPERABLE FILM-ADVANCING APPARATUS issued to Vaito K. Eloranta and Benjamin C. Ruggles on Sept. 11, 1973, and U.S. Pat. No. 3,810,210 entitled FILM UNIT PROCESSING MECHANISM issued to Henry S. Adamski and Gilford E. Kindig on May 7, 1974. The former includes a crank power input and the latter a lanyard power input.
Both of the aforementioned systems may be characterized as being relatively complex expensive mechanisms since they employ the use of multiple gears and either a clutch or cam arrangement to terminate the power drive relationship between the rotating rollers and the film advance.
The present invention, however, as the result of a different principle of operation, represents a simplified, less expensive manual processing system capable of meeting the functional requirements without the use of any gears or cams.